Fuel injection system for an internal combustion engine



July 7, 1959 c. M. ELLIOTT ETAL 2,393,364

FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE 5 Sheets-Sheet 1Filed April 10, 1956 VENTORS. 67170 071 f; Z'ZZzaZZ gear] .5. A a/2,yrra FIVE/Sf July 7, 1959 c. M. ELLIOTT ET AL 2,893,364

FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE Filed April 10,1956 5 Sheets-Sheet 2 INVENTORS CZi/i o 71 M JZZz'a/E.

WAJQL- irraxwz/s' July 7, 1959 c. M ELLIOTT ETAL 2,893,364

FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE 5 Sheets-Sheet 3Filed April 10, 1956 d a w 7. S J i M, A m z W /IA I /WWMWZ/ NH a, i m WWA]; fi a 11 M N 0/ J z m i m A. J v w 4 I 4 z y 1 r u I 5 .1 W "M w hmwmk ufi I 4 72 4 .1 U; 2 w? a. B Z I 0 n :M a m v a .w\m g RMUKU i z aa M J July 7, 1959 C. M. ELLIOTT ET AL FUEL INJECTION SYSTEM FOR ANINTERNAL COMBUSTION ENGINE Filed April 10, 1956 5 Sheets- -Sheet 4 V ENTORS 677/2271 )9 zzzzbzz.

gear? J? #07 71 July 7, 1959 c. M. ELLIOTT ETAL 2,893,354

FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE Filed April 10,1956 5 Sheets-Sheet 5 VENTORS 672/7071 IZZzaZ FUEL INJECTION. SYSTEMFORAN COMBUSTION ENGINE,

Clifton M. Elliott and, Mearl ,E. Noftz, Birmingham, Mich, assignors toChrysler Corporation, Highland Park, Mich., a corporation of Delaware:

Application April 10, 1956,'S,erial,N0.:577,'6 27 2'5-Claims, (ClL'123-"-1-19)-' Our invention relates generally to a fuel system for aninternal combustion engine andymore particularly to a new andimproved-fuel injection system which is particularly adapted to beusedwith'spark' ignition engines and which is characterized by lowoperating fluid pressures.

Afuel injection system of the general type referred to above has beendisclosed in the copendingpatent-application of Jorma O. Sarto, SerialNo. -460;668-,: filed Octobe'r-6, 1954, .which is assigned to theassignee-of-ourinstan-t invention. Many of the constituent elements ofthe fuel system of the present'invention are disclosed-in .theabove-identified copending application. However,- this application is acontinuation-in-part of our-copendingapplication Serial No. 504,577,filed April'28',-1955', now abandoned, and relates to-a fuel systemhaving new-and improved speed sensor and load sensor units of simplifiedconstruction'cooperable' to provide a controlled supply ofliquid fuel tothe air atomizing nozzles associated with the engine cylinders.

The operating pressures of the fuel system:of our instant invention areof a low-order or magnitude in. comparison with the operating pressuresof fuel: injection systems of known construction. Asseparate nozzle isprovidedfor each of the. engine cylinders andtbyvpreference, a separateintake air conduit-tor ram tube .is provided for each of the enginecylinders. An air distribution chamber is provided for supplyingeachoftheram tubes with a uniform inlet air supply.

The: provision of an improvedfuel'injection system being a principalobject of our instant invention, further objects are to provide needlevalve controlled load sensor and speed sensor units of improvedconstruction, .the. load sensorxunit being characterized. by.improvedresilient means for-biasing the needle valve, in accordance.withthe engine load requirements/the speedlsensor unit vcomprising aunique! and highly efli'cient-mechanicalgovernor means cooperable withthe load sensornnit for adjustably positioning the needle valve of thespeedzsensor unit to assure optimum fuel delivery at substantiallyalliengine speeds.

Itis-a further object of our instant invention toprovide a speed sensorof the type referred to above'wherein the adjustable needle valveelement, the flow. restricting orifice,.. and the mechanical governor.meansareconcentricallyarranged ina compact, efiicientarrangement.

It is a further object of our instant invention to provide a speedsensor for use-witha fuel injection system as setforth above, whereinsaid adjustable needlevalve is carried by a movable diaphragm, andwherein fluid passage means are provided for subjecting said diaphragmto =the pressure drop-across'the flow metering orifice associated withthe load sensor unit.

It is a further object of our instant invention to-providev anew andimproved means for-sealingthe fluid pressure which is. disposed acrossthe movable diaphragm of the-speed sensor unit-referredtorin-';the:preeeding object.

Still another object. is to provide an improvedfuel metering systemofthe above character comprising ,co-. operatingload sensor. and speedsensor unitsin series.

and improved means for adjusting the needle valve., of the speed sensorunit to control the flow of fluid to the,

tire fuel injection system pf whichrthe speed sensorunit of ourinstantinvention forms a part;

Figure 2 is a cross sectional view of a starting unit. Which-forms aportion of thefuel injection system shown in Figure l;'

Figure 3 is across sectional viewof a load sensor metering mechanismwhich forms a portion of the fuel system of Figure .1;

Figure 3A is. a graphic representation of the relation-. ship betweenenginemanifold pressure and engine power and fuel delivery through theload sensor orifice;

Figure 4 is a cross sectional view showing the detail, construction ofthe speed sensor unit of our instantiavention, said speed sensor unitbeing adapted to be used with the fuel injection system of Figure 1;

Figure 4A is an enlarged fragmentary schematic view of a portion of thegovernor mechanism of Figure 4, illustrating the relationship betweenthe locations of the centers of gravity and pivot axes of the governorweights and their engagements with the actuating means for speed sensorneedle valve;

Figure 5 is a plan view of an engine-powered fuel and air pumping unitwhich is adapted to be used with the fuel system of Figure. 1 forsupplying a .plurality of air atomizing nozzles with a supply of liquidfueland air;

Figure .6. is a crosssectional view of the upper portion of the fuel andair pumping unit of Figure 5 and taken along section line 6-6 of Figure5;

Figure 7-is a vertical cross sectional view of the fuel and air pumpingunitpof Figure 5 and is taken along section line 77 of Figure ,5;

Figure- 8 isa view showing a portion of the check valve system for theairpumping portion of the fuel and air pumping unit of Figure 5 asviewed along section line 8'- f Figure 7; and

Figure 9 is a cross sectional view of an accelerator pumping mechanismwhich is adapted to be used with and to forma POItiOD'Of thC fuel systemof Figure 1.

Referring first to Figure l, the numeral 10 is used to generallydesignate the vehicle engine and it comprises a flywheel 12 powered byand coupled to an outwardly ex; tending --portion 14 of the enginecrankshaft. The engine illustrated in Figure 1 is of a V-8 configurationhaving two banks of cylinders, as shown at 16 and 18, upon which aresecured a cylinder head and manifold structure shownat 20 and 22respectively. However, it will be apparent that the fuel injectionsystem of our instant invention-is capable of being used with many othertypes of internal combustion engines including multiple cylinder inline" engines and opposed cylinder engines or the like. A plurality ofindividual intake conduits 24.are provided as shown with a separateconduitcommunicating with each of the plurality of engine cylinders.-The conduits, 24 function as ram tubes and their. lengths may be chosenso that the optimum ram effect may be obtainedthroughout the normaloperating speed and load ranges of the engine. Each of the conduits 24communicates -,with,an intake air distribution chamber or plenum chamber26.- The chamber 26 maybe suppliedby onenr moreconduits- 2.8.:1whichmay-be connectedto an intake a ented Ju y ,1959

filter and cleaner assembly 30 situated at the upstream end thereof.

The principal components of the fuel injection system herein disclosedinclude a fuel and air pumping unit 32, a load sensor unit 34, astarting unit 36, an accelerator pumping mechanism 38, a check valve 40,a plurality of air atomizing nozzles 42, and a speed sensor unit 44.Suitable conduit structure is provided for interconnecting the variousindividual components of the fuel system, said conduit structureincluding a fuel delivery conduit 46 extending from the discharge sideof the fuel pumping portion of the fuel and air pumping unit 32 to thespeed sensor unit 44.

Another conduit 48 is adapted to conduct fuel from the speed sensor unit44 to the inlet side of the load sensor unit 34. The fuel is thenconducted from the load sensor unit 34 to each of the individual airatomizing nozzles 42 through a conduit50. An air delivery conduit 52extends from the discharge side of the air pumping portion of the fueland air pumping unit 32 to each of the individual air atomizing nozzles42 as shown. The air pumping portion of the fuel and air pumping unit 32is double-acting as will be subsequently explained, and it is thereforeprovided with a second air delivery conduit 54 which communicates withthe air delivery conduit 52 to supply the air atomizing nozzles 42 withfuel atomizing air during the half cycle of the pumping operation whenair is not delivered through the delivery conduit 52.

A bypass conduit 41 extends from the fuel delivery conduit 46 to theintake side of the accelerator pumping mechanism 38 and another bypassconduit 43 extends from the outlet side of the pumping mechanism 38 tothe conduit 50. The check valve 40 is adapted to accommodate the flow offuel from the pumping unit 38 into the conduit 50 and to prevent a backflow into the pumping mechanism 38 or into the load sensor 34. Theaccelerator pumping mechanism 38 is actuated by the engine throttlelinkage and is effective to supply the nozzles 42 with an additionalcharge of fuel to facilitate rapid acceleration.

A throttle valve element 56 is disposed within each of the intakeconduits 24 on the downstream side of the air atomizing nozzle 42 forthe purpose of regulating the rate of supply of combustible mixture tothe individual engine cylinders. An intake manifold vacuum conduit 58extends from at least one of the intake conduits 24 on the downstreamside of the associated throttle valve element 56 to the load sensor unit34 as indicated. A fuel drain line 60 extends from a portion of the loadsensor unit 34 to one of the air intake ports of the fuel and airpumping unit 32.

A branch conduit 62 extends from the conduit 50 for the purpose oftransmitting a fuel pressure on the downstream side of the load sensorunit 34 to the speed sensor unit 44. A bypass conduit 64 extends fromthe fuel delivery conduit 46 to the above-mentioned starting unit 36 andanother conduit 66 is provided for connecting the outlet side of thestarting unit 36 to the fuel conduit 50. By preference, a suitable Ttype connection 68 is used for interconnecting the conduits 50, 62, and66. The bypass conduits 64 and 66 are adapted to accommodate anauxiliary flow of fuel from the fuel and air pumping unit 32 to theindividual or atomizing nozzles 42 during the engine starting operation,and the starting unit 36 is adapted to regulate the rate of flow of thisadditional fuel to that which is required to initiate and to maintaincombustion during starting.

V Referring next to Figure 2, we have illustrated in more particulardetail, the construction of the starting unit 36. The starting unit 36comprises a body portion 70 formed with a first bore 72 within which anidle metering unit 74 may be disposed. The idle metering unit 74comprises an insert 76 having an axially extending opening therethroughas shown at 78. A metering orifice means 80 is disposed within theinternal opening 78 and an 4 adjustable metering element 82 may beaxially positioned within the orifice means 80 in registry therewith.The metering element 82 is carried by a manually adjustable stem 84which may be threadably received within the opening 78 and which mayinclude an outwardly extending portion 86 to accommodatea suitable handtool or the like. By preference, the metering element 82 is formed witha tapered opening at the extreme end 88 thereof, said tapered openingcooperating with the orifice means 80 to provide a variable restrictionas the shank portion 84 is adjusted axially within the opening 78. Theinsert 76 may be retained in place by means of threads 90 formed on oneportion of the outer periphery thereof and on a portion of the interiorof the bore 72. Suitable O-ring type seals may be provided as shown at92, 94 and 96 for the purpose of etfectively sealing the insert 76 andthe shank portion 84 of the adjustable metering element The bypassconduit 64 is secured to the body portion 70 of the starting unit 36 bya threaded fitting 98 and it communicates with the central opening 78 ofthe insert 76 through ports 100. The bypass conduit 66 is secured to thebody portion 70 by means of a suitable fitting 102 and also itcommunicates with the bore 72 as shown.

A second bore 104 is formed within the body portion 70 of the startingunit 36 and it also contains a hollow insert as shown at 106. Thisinsert 106 may be identical in construction with the above-describedinsert 76 and it may include a metering orifice 108 Within which ametering element 110 is adjustably positioned. The metering element 110may be identical in construction to the previously described meteringelement 82 and it may be adjusted by manually rotating the meteringelement shank portion 112.

A bypass passage 114 is provided for interconnecting the bore 72 withthe bore 104, and ports 116 are provided for interconnecting the conduit114 with the interior of the insert 106.

A reduced diameter portion of the bore 104 is shown at 118 and it isadapted to receive a hollow insert 120 having an orifice 122 formed atone end thereof as shown. A metering element 124 is positioned withinthe hollow insert 120 in registery with the metering orifice 122, and itis carried by a guide member 126, said guide member being telescopicallyreceived within the hollow insert 120. A radially extending flange 128is carried at the upper end of the guide member 126 and is positioned onthe exterior of the body portion 70. A plate 130 is secured to the bodyportion 70 by means of bolts 132 and it is provided with a recess 134for receiving the flange 128, said flange being adapted to movevertically within the recess 134. A spring 136 is interposed between theplate 130 and the metering element 124 for normally biasing the latterin a downward direction so as to restrict the metering orifice 122. Asolenoid 138 may be secured to the plate 130 in substantial alignmentwith the guide element 126 and it may be enclosed by a suitable housing140, the latter being secured to the body portion 70 by bolts 142.Suitable means may be provided for energizing the solenoid 138 withengine ignition current when the engine operating temperatures are belowa predetermined optimum value thereby causing the metering element 124and its associated guide element 126 to move vertically upward, asviewed in Figure 2, thereby opening the flow metering orifice 122 toaccommodate a greater flow of fuel therethrough. When the engine reachesa predetermined operating temperature, the solenoid 138 becomesdeenergized and the metering element 124 is returned to its flowrestricting position under the influence of the spring 136. Abimetallic'thermostatic switch or some other temperature responsiveswitch means may be used in a conventional manner for selectivelycontrolling the flow of ignition current through the solenoid 138. Anadditional bypass passage 144 and an orifice 146 in the insert 120provide communication between the interior oi -the element=120 and-thepreviously described-bore 72; It wit-1 therefore, :be apparent .that:the' flow of.:fue1-from the conduit 64 -throughrthegbore 72 and intotheconduit 66'will'be supplemented by "an additional bypass flowthrough-the bypass passage 114,-the port 116,-orifice 108, bore104;orifice '122,-ports-146-, and the bypass passage 144: Howevergthisbypass fiowis obtained only when the engine operatingtemperaturesarebelowthe predetermined optimum value as above explained.

A third bore 147 is provided withinthe housingbody portion 70 and it isadapted to receive aninsert 148 within which is formed a flow'metering,orifice 150, the bore l47 communicating with the bore 104 in theinterior ofrthe-insert-106 as-indicated. A'flow metering element 152 isslidablyreceived withintheinsert 148 in registry with theorifice -150and-.it'includes a large diameter portion 154'and'a transverse fiangeportion 156, the former accommodating a spring/for normally biasing-theflow metering'element'152 toward the left, as viewed in Figure 2, andthe latter being situated within recess 158 formed in aside plate1-60secured to the body-portion 70 by bolts 162. A solenoid element 164:is'secured to theplate 162 insubstantial alignment with the flowmetering element 152 and it isenclosed by a suitable housing 166- whichmay: be secured to the body portion '70 by a bolt 168. Suitable meansmay be provided for energizing the sole noid element 164 with ignitioncurrentas. the engine starter switch is closed thereby causing themetering .ele; ment 152 to move totheright, as viewedin Figure 2, duringthe cranking operation of the engine. The bore 146-comn1unicates withthe bore 104' on the downstream side of the orifice 108 by means ofintersecting passages .170 and 172 passage 170 communicating with theinterior of the insert 148 'by means of ports 174.

Iri operation the restriction provided bythe orifice 80 may be manuallyadjusted so as to provide an idle bypass flow of apredeterminedmagnitudel It will be apparent from the schematic view ofFigure 1 that this idle bypass flow supplements the flow of fuel throughthe speed sensor unit 44 and the load sensor unit 34, and when the fuelinjection system is used with a conventional automotive type'engine, itis desirable to regulate this idle bypass fiow to a value approximatelyequal to 4 lbs. per hour. During the warm up period for such an engine,the flow metering orifice 122 will be'opened and an additional flow ofapproximately 2 lbs. per hour will be bypassed therethrough, the flowmetering element 110 being manually adjusted with respect to the flowmetering orifice 108 to accommodate the additional flow required. Duringthe engine cranking operation it is desirable to provide an additionalflow of approximately 20 lbs. per hour and the flow metering orifice 150is accordingly'adapted to accommodate such a flow as the meteringelement 152 is moved to the right by the solenoid control 164. It willbe observed that the metering orifice 122 is located on the downstreamside of each of the. orifices 108 and 150 so that the additional bypassfiow during the warm up period and during the engine cranking operationis not obtained while the engine is warm.

Referring next to Figure 3, we have shown a cross sectional view of theload sensor unit for the above-described fuel injection system anditcomprises a first housing portion 176 and a second housing portion 178,said housing portions being separated by a gasket 180; Suitable boltmeans or the like may be provided for clamping the housing portions 176and 178 together. The lower housing portion 176 is provided with acentral chamber'182 and an opening 184 extends from the chamber 182 totheexterior of the housing portion 176. A hollow insert 186 ispositioned within the opening 184 and is threadably retained therein bymeans of threads 188. A flow metering orifice 190 is formed at theinner. end of. the insert 186 and a tapered'metering element-192 ispositioned within the hollow interior of theinsert 186 in registry withthe new meteringsorifice 19.0.; Suitable seals-194 may be 6 provided'for'preventing"leakingijbetween :the insert 186 andthe bore 184- A'fuelpassage 200is formedin the housingtportion 176 and an intersectingpassage 202 is formed in the housing portions 176 and 178,asshowmsaidpassage 202 communicating with-thefuel conduit 48"which'extends from the speed sensor unit 44 as previously described, asuitable fitting 204: being provided for this purpose.- The passage200-communicates with the interior of the hollow insert 186- throughajport 206; By preference, a second pair of intersecting-passages-200'-and 202. may be provided in another location within the housing portions176 and 178, said passages also communicating with the fuel conduit 48-to provide a secondsfuel delivery path.: Thefuelconduit 50, previouslydescribed, communicateswith thecene tral chamber 182througha port 206, asuitable.fitting.208 being provided to effect a suitable connectionbetweenthe port'206 and the conduit 50.

The housing portion 178 is formed with a hollow extension 210 withinwhich is slidably. disposed a piston memher 214. A Theextremity of theextensiona210 threadably receives a closure member 216. which inturnthreadably receives a fitting 218 for etfecting a connection with thevacuum conduit 58, previously described.

The piston 214 carries a shaft element 220 on one side thereof and it.is slidably received through. a bushing: 222, the-latter being insertedin an opening 224 extending from the central chamber 182 tov theinterior of the housing extension 210. By preference, the-taperedmetering ele.- ment 192 iscarriedby the extremity of the shaftelement220 as indicated, and is adjustably positioned with respect to themeteringorifice 190 as the piston 214=is moved with respect to theextension 210. A pairof springs, as shown at 226 and at 228, areinterposedbetween the piston 214 and the closure member 216, .the spring228 havinga lower spring. rate thanthe spring 226. The spring 228 urgesthe piston 214 away from the closure member 216 throughout the entireoperating stroke of the piston 214' while the spring 226' becomesunseated throughout a portion of the operating stroke of the piston 214,the free height of the spring 226 being less than the axial length ofthe hollow interior of the housing extension 210.

The drain conduit 60 communicates with the hollow interior of the pistonextension 210 and it is adapted to accommodate any leakage of fuel pastthe bushing 222.

The chamber within the hollow extension .210 on one side of the piston214 communicates with the ambient air through a vent 230.

During operation of the engine, a variation in engine load will beaccompanied by a variation in the intake manifold vacuum pressure whichin turn is communicated to the hollow interior of the housing extension210 through the vacuum conduit 58. An increase .in manifold vacuum willcause the piston 214 to move against the biasing force of the springs226' and 228 so as to restrict the flow of fuel to the metering orifice190, thereby reducing the rate of fuel delivery to the air atomizingnozzles42. Upon an increase in load, the manifold vacuum decreases whichin turn causesan increase in the fuel delivery rate.

' With an engine of the type. previously described, the manifoldpressure varies non-uniformly with changes inthe power delivered by theengine, and it is therefore imr portant that the load sensor unit 34should accordingly vary the rate of fuel delivery so as to meet the fuelre quirements of the engine over the entire operating range of theengine. For example, when the engine output power varies from of maximumto approximately 50% of maximum, thevariation in engine intake manifold.pressure may vary only about 3 inches. of mercury. However, a variationin the power outputfor the engine from approximately 50% of maximum to ais accompanied by a variation in the intake :manifold pressure ofabout-15 inches ofmercury. .Eorrthis reasom the lower rate spring 228 isemployed for biasing the piston 214 asthe engine output power variesfrom a maximum to approximately 50% of maximum. As the engine outputpower varies from approximately 50% of maximum toa minimum, both of thesprings 226 and 228 are employed for biasing the piston 214. Theeffective spring rate for both of the springs 228 and 226 thereforevaries in magnitude from a lower value in the high power outputoperating range to a higher value in the lower power output operatingrange. Consequently, the position of the metering element 192 variessubstantially linearly with the engine power output.

The operation of the load sensor unit is illustrated by thesemi-logarithmetic diagram of Figure 3A wherein curve 1 represents ageneralized relationship between the absolute manifold pressure and thepercentage of the total engine power being delivered for a givenconstant engine speed. Curve 2 represents the variation in the openingor orifice 190 and correspondingly of fuel flow therethrough for variousmanifold pressures throughout the movement of piston 214 that is opposedsolely by spring 228. Curve 3 similarly represents the extent of openingof orifice 190 and the flow of fuel throughout the movement of piston214 that is opposed by both springs 226 and 228. The combined curves 2and 3 closely approximate curve 1 so as to compensate adequately for thelatters non-linear characteristics, whereby the rate of fuel deliveredto the engine is at all times approximately equal to the fuel requiredat any given manifold pressure.

Referring next to Figure 4, we have illustrated the details of theconstruction of the speed sensor unit 44 and it includes a pair ofjuxtaposed housing portions 232 and 234 which may be secured together bybolts 236. Each of the housing portions 232 and 234 are provided withrecessed interiors which cooperate to define a central chamber 238. Aflexible diaphragm 240 is disposed transversely across the chamber 238and is secured about its periphery between the juxtaposed surfaces ofthe housing portions 232 and 234 so as to define a pair of opposedchambers identified by the numerals 242 and 244.

One side of the housing portion 232 is recessed, as shown at 246, and aring member 248 is seated within the recess 246, said ring member beingsecured to the housing portion 232 by screws 250. A second flexiblediaphragm 252 is transversely disposed across the central opening of thering 248 and is secured about its periphery between the juxtaposedsurfaces of the ring 248 and the adjacent housing portion 232. Thediaphragrns 252 and 240 are joined together for operation in tandem by ashaft 254. A pair of backup plates 256 and 258 are carried at one end ofthe shaft 254 and are secured thereon by a set screw 260. Similarly, apair of diaphragm backup plates 262 and 264 are carried by the other endof the shaft 254 and are secured thereon by a suitable set screw 266.The housing portion 234 is provided with a central threaded aperture 268within which a hollow metering insert 270 is threadably received. A flowrestricting orifice 272 is formed in the metering insert 270 and ametering element 274 is slidably received within the hollow interior ofthe metering insert 270, said metering element 274 being adapted toregister with the metering orifice 272 for controlling the degree ofrestriction thereof. A fitting 276 is threadably received over the endof the metering insert 270 to facilitate a connection with the fuelconduit 46 previously described, and a spring 278 may be interposedbetween the fitting 276 and the metering element 274 for biasing thelatter toward the metering orifice 2721. The metering element 274-includes an extension 280 which extends through the orifice 272 andcentrally contacts the end of the shaft 254.

The chamber 242 within the housing portion 234 communicates with theabove-described fuel conduit 48, a suitable fitting 282 being providedfor this purpose. Simi- 8 larly, the chamber 244 within the housingportion 232 communicates with the above-described conduit 62, anothersuitable fitting 284 being provided for this purpose.

A housing extension 286 is bolted on one side of the housing portion 232and it encloses a speed governor mechanism generally designated bynumeral 288. The governor mechanism 288 includes a pair of centrifugalcounterweights 290 and 292 which are respectively pivoted at 294 and 296to a carrier 298, the latter being secured to a supporting shaft 300. Ashaft extension 302 extends from the shaft 300 toward the diaphragm 252and it slidably carries a sleeve member 304. A flange 306 is formed atone end of the sleeve member 304 and the other end thereof is adapted tocontact the screw 260. The shaft 300 is rotatably journalled in thehousing extension 286 by means of bearings 308 and 310, the latter beingengaged by a spacer element 312. By preference, a seal 314 may beprovided as shown for containing bearing lubrication within the housingextension 286. The shaft 300 is formed with a reduced diameter portion316 over which a sleeve member 318 is received and a pin 320 is providedfor securing the sleeve 318 and the shaft portion 316 together. Aflexible cable 322 may be secured at one end thereof to the sleeve 318by a suitable key 324 or by any other suitable fastening means, theother end of the cable may be powered by the engine crankshaft in aconventional manner.

In operation, the engine driven cable 322 is effective to notate thecarrier member 298 and the centrifugal weights 290 and 292 within thehousing extension 286. Upon an increase in speed, the sleeve 304 ismoved to the left, as viewed in Figure 4, by reason of the engagement ofthe flange 306 with notches 326 and 328 formed in the centrifugalweights 290 and 292. Upon movement to the left, sleeve 304 biases thediaphragm shaft 254 to the left thereby causing the metering element 274to move to the left against the opposing force of the spring 278. Thisdecreases the degree of restriction of the fuel metering orifice 272thereby providing an increased flow of fuel to the fuel conduit 48.

As illustrated in Figure 4A, the arrangement and location of the centerof gravity, C.G., of each of the weights 290 and 292 with respect to itspivot axis 294 or 296 and its notch 326 or 328 is important for properfunctioning of the speed sensor device at all engine speeds. Thecentrifugal force acting through the centers of gravity and depending topivot the weights 290, 292 about their pivots 294, 296 is pnoportionalto the square of the engine speed which determines the speed of rotationof the shaft 322. When the center of gravity of each weight 290 or 292is at an intermediate position on a line parallel to the axis ofrotation of the shaft 300 and passing through the corresponding pivotaxis of the weight, the centrifugal force leverage urging axial movementof sleeve 304 is a maximum. This leverage decreases as the center ofgravity moves in either radial direction from the aforesaid intermediateposition. It has been found that unless the extreme range of movement ofthe centers of gravity from their intermediate position is comparativelysmall, the centrifugal force leverage urging the sleeve 304 axially willbe too great at low engine speeds in comparison to the correspondingleverage at high engine speeds. In order to obtain adequate fuel forhigh speed engine operation in such a situation, the speed sensormechanism must be over-compensated to deliver excess fuel at low speeds.

The present construction overcomes the foregoing difficulty by thearrangement of the weights 290 and 292 shown wherein the centers ofgravity at the extreme limits of movement are adjacent and spaced bytheir aforesaid intermediate positions. Radially outward swinging !Ofthe weights 290, 292 beyond the solid line position shown in Figure 4 islimited by abutment of the outer generallyradial shoulders of theweights at their right hand ends-with -the radial b'aseof thecarrier-298w Radi allytinward swinging-cf the-weights beyoiidthe dottedposition shown in Figure 4A islimited by abutment' 'of theirradial inner'edges witlrsleeve'304." Within "the range of movements of the weights290, 292 betweenthe solid line position-"(maximum fue1' delivery) andthe dotted line position (minimum fuel delivery) thecentn'fugal forceleverage urging leftward axial moveriientof sleeve 304 is substantiallyconstantand at its maximum. Within this range however the"axial-displacement of the sleeve'304 for a given swinging movement ofthe-weights 290, 292 is a minimum. Movement of -the sleeve 304 to effectadequate movement of the metering element-274 is-- achieved with thestructure shown by*maintainiirg the lever armlength A fromeachpivot 294or 296'to'th'e corresponding notch 326px 328, greater, than 'thc'leverarm length B'from each pivot 294 r296 tothe-cor respondingrcenterinf-gravity. Thus any given swinging movementof the centers ofgravityabout their 'pivots 294 and- 296 is magnified and converted toaxial'movement of the sleeve 304.

Byvirtue of the arrangement of the 'centers' of gravity on leverarms B,which are shorter thanth'e lever arrns A- and which are pivotaloutwardly and inwardly of the above-defined intermediate positionslocated on lines through the pivot axes 294, 296 and parallel to theaxis of -rotation of the governor means, axial movement of the sleeve304 is approximately directly proportional to' the swinging movement ofthe weights290, 292 though out-the entire operating speed rangeof theengine; Also the; leftward axial force exerted by sleeve304 urgingdiaphragm 240 leftward in Figure 4 and-openingorifice 272is-approximately proportional to thesquareof the engine speed, so thatproper fuel delivery is accomplished throughoutsubstantially "the entireenginespeed range.

Referringnext to Figures 5 through 8, we have disclosed a fuel orpumping'unit which is particularly adapted to be used with the fuelinjection system herein disclosed, and it-comprises an intermediatehousing por-' tion 330, an upper housing portion 332,an'd a lowerhousing portion 334. The upper surface of :the inter mediate housingportion 330 is recessed,-as shown at 336, and the lower portion of theupper housing portion 332 is recessed, as shown at 338 Each of therecesse's336 and 338 define separate'air pumping chambers which areseparated by a flexible diaphragm memher 340, said diaphragm member340being secured about its periphery between the juxtaposed surfaces of theupper housing portion 332 and the intermediate housing portion 330.Screws 342 may be provided forsecuring the upper housing portion 332 in'place as shown. A pair of diaphragm backup plates 344 and 346 isdisposed on either side of the diaphragmmember340 and a verticallydisposed shaft 348 is secured centrallyto the backup plates 344 and346-as shown. An air-diaphragm spring 350 is interposed between thebackup plate 344' and the interior of the housing :portion'332'forbiasing the'diaphragm 340 in a downward direction.

As best seen in Figure 5, the upper housing portion 332 isprovided withan inlet and outlet passagei'shown at-352 and 354 respectively. A port356' may beprovided in the upper housing portion332 toprovidecommunication between the outlet passage354' and the above mentioned airpassage 54; Similarly, a port 358 may be provided in thehousing portion332' to provide communication between the inlet port 352 and the drainpassage 60, said drain passage being adapted to accommodate the flow ofinlet air to the'working chamber defined by the recess-338.

Referring next to Figure 6, we have shown in more particular-detail theconstruction of the inlet andou'tlet air pas-sages 352 and 354 and theyeach include-a check valve 'device to accommodate a one-way flow of 1air the'rethrough.' The checkvalve'associated' with passage 352:includescani:apertured plate360 and a muvauevalve plate 362 i whichselectively opens and closesthe apertures of the plate 360: An open cage364 isprovided for containing the movable valve plate 362 and'a-retainerpin 366 may be provided as indicated for securingthe'cage-364-to' the apertured plate 360. The check valvev associatedwith the outlet air'passage'354 is similar'in construction to the checkvalve described above and it includes an apertured 1 plate 368 disposedtransversely across-the passage 354, a movable plate 370 and a cage 372,the latter being secured to the plate 368 by a retainer pin 374.

Referring next to Figures 7 and-8, a check valve housing 376 is securedto the" intermediatehousing porti'on 330- below the air-working chamberdefined bythe recess 336; An inlet air passage and an outlet airpassageare formed in the housing 376, asshown at 378 and 380 respectively,the-former communicating with a suitable air inlet connection, notspecifically shown, and the latter communicating with 'the'air deliveryconduit 52,-'-ports- 382- and 384 being provided forthis purpose-1- Eachof-the passages 378 and 380 includes a one-way check valve mechanismgenerally designated in Figure 7 by-num'eral 386, eachof said mechanismsbeing similar to tho'seillustrat'ed in Figure 6.

The lower portion'of-the intermediate housing portion 330 includes aspring chamber 388 across which a fuel diaphragm 390 is'disposed. Thelower housing portion 334' is recessed at 392 to define a fuel workingchamber below the fuel diaphragm- 390 and the periphery of the diaphragm390 is secured between the juxtaposed surfacesof the'housing portions330*an'd 334'. A fuel outlet passage 394 is formed within thehousingportion-334' and it is adapted to' be connected to fuel delivery conduit46, previously described. A suitable fuel'inlet passage for the fuelworking chamber 392 may also be provided for maintaining a supply ofcombustible fuel within the fuel working chamber. The fuel inlet andoutlet passages for the fuelwork ing chamber may be formed with suitableone-way check valve mechanismsof known construction.

A pair of backup plates 396 and 398 are disposed on either side ofthe-fuel diaphragm 390 and an actuat ing shaft 400' is centrally securedthereto as shown. A fuel spring 402 is disposed within the springchamber 388 and it is eifective'to bias the fuel diaphragm 390," asviewed in Figure 7. The actuating shaft 400 extends vertically upwardinto a transverse opening 404 formed in the intermediate housing portion330. An operating lever 406 is pivoted at 408 within the opening 404 andit is connected to the actuating shaft 400a: the inner endthereof'bymeans of a lost motion connection generally designated bynumeral 410. The inner end of the lever 406 also engages the airdiaphragm actuating shaft 348 to'- provide a one-way mechanicalconnection between lever 406 and shaft 348. As the lever 406 is rotatedin a clockwise direction, the fuel diaphragm actuating shaft 400 ismoved with an upward intake stroke and the" air diaphragm actuatingshaft 348 is simultaneously moved upwardly to provide a compressionstroke for the upper air working chamber and an' air intake stroke forthe lower air' workingchamber. Upon movement of the lever 406' in acounterclockwise direction, the air spring 350 moves the air diaphragm340 ina downward direction to provide an air intake stroke for the airworking chamber defined by recess 338 and a compression 'strokefor theair Working chamber defined'by recess 336. Similarly, the fuelspring'402 biases the fuel diaphragm-390 in a downward direction toprovide a Working stroke for the fuel working chamber defined by recess392. The lever 406 may be actuated'by a suitable cam connection with theengine crankshaft; one-end of the lever 406 being provided-with a camfollower" element 41 2-for thispurpose.

Referring next to Figure 9,- the accelerator pumping mechanism 38includes a central cylindrical housing portion 414 and two end housingportions '416 and 418. A working diaphragm 420 is disposed transverselyacross one end of the intermediate housing portion 414 and is securedabout its periphery between the juxtaposed sur faces of the housingportions 414 and the end housing portion 416. Similarly, a sealingdiaphragm 422 is transversely disposed across the other end of theintermediate housing portion 414 and is secured about its peripherybetween the intermediate housing portion 414 and the end housingportion'418. A transverse wall 424 is disposed across the interior ofthe housing portion 414 and is adapted to slidably receive the diaphragmactuating shaft 426. A check valve mechanism 428 is provided foraccommodating the unidirectional flow of fuel from the chamber definedby the wall 424 and the sealing diaphragm 422 to the working chamberdefined by the wall 424 and the working diaphragm 420. The chamber whichis partly defined by the sealing diaphragm 422 is in fluid communicationwith the above-described fuel condit 41, a suitable fitting 430 beingprovided for this purpose. Similarly, the working chamber partly definedby the working diaphragm 420 is in fluid communication with theabove-described fuel conduit 43, a suitable fitting 432 being providedfor this purpose. The diaphragm actuating shaft 426 may be connected tothe engine accelerator linkage mechanism by means of a lost motionconnection, and upon movement of the throttle valves toward an openthrottle position, an accelerator pumping spring, not shown, may biasthe diaphragm actuating shaft 426 toward the right, as viewed in Figure9, thereby causing a charge of fuel to be delivered to the fuel conduit43 into the fuel delivery conduit 50 and the nozzles 42. The check valve40 between the conduits 43 and 50 is effective to prevent this auxiliarycharge from entering the fuel outlet port or the load sensor unit 34 andfor preventing a return flow of fuel from the conduit 50 into theconduit 43.

During operation of the engine, the rocker arm 406 of the fuel and airpumping unit 32 is adapted to be actuated by the engine camshaft therebycausing the fuel and air diaphragm to' become deflected. The air pumpingportion of the pumping unit 32 is double acting, the air diaphragm beingpositively controlled in the upward direction and spring biased in theother direction. The working stroke of the fuel pumping portion of theunit 32 is single acting and the pumping stroke takes place by virtue ofthe force exerted by the fuel spring 402.

Upon an increase in engine load while the engine speed remains constant,the engine manifold pressure increases, and therefore the piston member214 of the load sensor unit 34 is urged in a downward direction toincrease the effective opening of the metering orifice 190. This tendsto increase the total flow through the load sensor unit and to decreasethe pressure drop across the metering orifice 190. This pressure drop istransmitted across the diaphragm 240 of the speed sensor unit which inturn causes the metering element 274 to move away from orifice 272 andto increase the effective opening of the latter. This in turn results inan increased fuel fiow to accommodate the increased fuel requirements,and since the rate of flow of fuel through the orifice 190 of the loadsensor unit is correspondingly increased, the pressure drop across theorifice tends to increase to that value which existed before the engineload was changed. Thus, the pressure drop across the diaphragm 240 ofthe speed sensor unit is not affected by variations in engine load. Thedimensions of the tapered metering element 192 of the load sensor unitare chosen so as to make this characteristic possible. 7

Further as explained above, the characteristics of the governormechanism 288 of the speed sensor unit are such that the net axial forceexerted on the sleeve 3G4 and diaphragm shaft 254 by the weights 290 and292 will remain substantially constant for any given speed of rotationregardless of the radial position of the weights 290 and 292 or theaxial position of the diaphragms 240 and 252. This axial force willresult from the centrifugal force on the weights 290 and 292 and willthus be a direct function of the engine speed which determines the speedof rotation of the weights 290 and 292.

It will be apparent from the foregoing description that the uniqueconstruction of the speed sensor unit 44 does not require a complexsealing element for containing the fluid within the chamber on eitherside of the diaphragm 240. The need for a seal about the diaphragm shaft254 is completely eliminated since it does not extend through astationary wall of the pressure chamber partly defined thereby. Theprovision of a sealing diaphragm 252, as described, effects a completelyenclosed fluid chamber and the net biasing force exerted by the meteringelement 274 is equal to the pressure force on diaphragm 240 less thepressure force on diaphragm 252. Such a construction greatly increasesthe sensitivity and reliability of the unit.

In addition, the compact and concentric arrangement of the constituentelements of the speed sensor unit 44 makes the same simple to constructand assemble and readily adapts the same to be used in commercial fuelinjection systems.

What we claim and desire to secure by United States Letters Patent is:

1. In a fuel control system for a liquid fuel engine having a fuelpressure source and a fuel delivery conduit extending from said sourceto said engine, an engine speed sensitive fuel metering unit including afuel metering orifice forming a portion of said fuel delivery conduit, amovable fuel metering element registering with said orifice forprogressively restricting the latter upon movement thereof, a firstflexible diaphragm disposed within said unit and partly defining a firstfuel chamber therein, said orifice communicating with said first fuelchamber, said metering element being adapted to be actuated by saidfirst diaphragm, a second sealing diaphragm coupled to said firstdiaphragm and disposed adjacent thereto, said first and seconddiaphragms defining a second fuel chamber, said second fuel chambercommunicating with said fuel delivery conduit at a downstream location,and a speed governor means having portions within said unit fordeflecting said coupled diaphgr-ams to vary the degree of restriction ofsaid metering orifice.

2. In a fuel control system for a liquid fuel engine having a fuelpressure source and a fuel delivery conduit extending from said sourceto said engine, an engine speed sensitive fuel metering mechanismincluding a housing, a fuel metering orifice in said housing forming aportion of said fuel delivery conduit, a movable fuel metering elementregistering with said orifice for progressively restricting the latterupon movement of said metering element, a first flexible diaphragm insaid housing partly defining a first fuel chamber on one side thereof,said first fuel chamber communicating with said orifice, said meteringelement being adapted to be actuated by said first diaphragm, a secondflexible diaphragm in said housing, means for coupling said first andsaid second diaphragms together for operation of the same in tandem,said first and second diaphragms defining a second fluid chambertherebetween, passage means interconnecting said second fuel chamberwith said fuel delivery conduit at a location downstream from said fuelmetering orifice, the fuel pressure differential between said first fuelchamher and said downstream location being effective to urge saidcoupled diaphragms in one axial direction, and engine speed responsivegovernor means for biasing said coupled diaphragms in the other axialdirection with a force which is a function of engine speed.

3. In a fuel control system for a liquid fuel engine having a fuelpressure source and a fuel delivery conduit extending from said sourceto said engine, an engine speed sensitive fuel metering mechanismsincluding a housing'r-a fuel metering-verifier: in said housing: forminga portion of said fuel delivery condiut,-- amovablefuel meteringrelementregistering-;;with said orifice for progressively restrictingthe latter upon movement ofsaid metering :elemen't, afirsr-fiexiblediaphragm in said housing partlydefiningqa first fuel chamber onone-side thereof,-.i' said?first-fuel chamber communicating withsaidorifice, said metering element being adaptedto be actuated by3saidfirst diaphragm;v a second'flexiblediaphragm in said housing-,v-means:for. couplingysaid first and said secondcdiaphragms togetherfor-operatiomof thesame in tandem, said--first and -second1 diaphragmsdefining a second fluid ichamber therebetween,- passage meansinterconnectin'g said second=fuel chamber with said fuel delivery:conduit at: a locationdownstream from said fuel metering: gorifice; thefuel" pressure differential between said first fflll :chamber and saiddownstreamlocation being eifectiveto urge saidcoupledrdiaphragms' in oneaxial: direction, 2 and engine speed responsive governor meansrforactuating saidcoupled diaphragmsin the'other. axial# direction, saidgovernor'means' including an axially movableazelemenh for engaging andactuating said diaphragm COHPlllJguIllfiflllSgmfill adaptor rotatablymounted within-said housing andcentrifugal weights carried by saidadaptor, said centrifugal-weightshaving portions engageable; with saidraxiallymovable element; v,4.Th'e combination -asset forth in claim 3whereinsaid secondrdiaphragrncis substantially smaller than'said first:diaphragmandwherein the characteristics of said governor mechanism? aresuchthat the axialforce exerted upon said-axially. movable element issubstantially constant at a given engine speed rega'rdless' of theaxial'position of said axially movable element.

5. The combination-as set forthin claim-'4 wherein said first and seconddiaphragms, said axially movable element,- andsaidcentrifugal-,weightsare coaxially arranged-.7,

;.6. -In-a .fuel injection system for an engine having atleast-oneengine cylinder with-an intake manifoldcondui-bcommunicatingiwith said cylinder, said system in cluding a lowpressure 'liquid fuel air atomizing nozzle means'for-supplyingisaidintake conduit witha combustiblevcharge of=atomized fuel, a lowpressurefuel andairpumpingunit for.-supplying' said nozzle with'liquidfuel andwfuel atomizing;air,r.and separate conduit means for-conductinggboth liquid fuel andairto said nozzle; an engine speedsensitive metering-mechanism comprisingna fuel metering-orifice disposedinua portion of said fuel conduit means'andanengine-load responsivemeteringvmechanism" disposed in saidv fuel conduit means onthedownstreamside of said metering orifice, said engine speedresponsivemetering mechanism includnig a housing,-';:; amovable fuel. meteringelement registering with said-.orificelfor progressively restricting thelatter upon movement thereof, a first flexible diaphragm in said;housing ,partly d'efinin'gga first-fuel chamber on one side thereof,saidfirst:fuelrchambericommunicating with said orifice-said meteringelement being adapted to be acmated by :said--first: diaphragm, atsecond flexible di'a phragmdn: said-housing; means for-coupling saidfirst. and said second diaphragms together: for operation ofthe samet intandem, said first'and second diaphragms defin in'gia second fuel,chamberitherebetwe'en, said first fuel chamber forming: a portion of:said fiuidconduitmeans intermediate saidmetering orifice-and said loadresponsive metering: mechanism; said second fuel chamber com--municatingwithsaid fluid conduit means on the downstream side of saidload: responsive meteringmechanism; thevfuel pressuredifferential acrosssaid load respon-. sivermetering mechanism being effective to bias saidcoupled diaphragms'in one axial direction, and an enginespeedr'esponsivegov'ernor meanszfor biasingsaid coupled diaphragms in the:-other axial direction with a force which i'srafimction'ofenginefspeed;

7. In afuel injection system'foran engine having rat least one enginecylinder with an intake manifoldcom duit communicating withsaidcylinder, said systemincludingralow pressure liquid fuel airatomizing nozzle means'for supplying said intake conduit with acombustible charge of atomized fuel, a low pressure fuel and air pumpingunit for supplying said nozzle 1 with liquid fuel and fuel atomizingair, and separate conduitmeans f0r-c0nductii1g both liquid fuel and airto said nozzle; a speed sensitive metering imechanism comprising a fuelmetering orifice disposed in a portion of said fuel conduit means and anengine load responsive metering mechanism disposed in said fuel conduitmeans on the down-' stream side of said metering orifice, said enginespeed responsive metering mechanism including a housing,;.a movable fuelmetering element registering with said orifice. for progressivelyrestricting the latter upon mo vement thereof, a first flexiblediaphragm in'said housingpartly defining a; first fuel chamber on" oneside thereof; said-first fuel chambercommunicating' with said orifice,said metering element-being adapted to be actuated by said firstdiaphragm, a second flexible diaphragm in said housing, means forcoupling said first and said second diaphragms together for operation ofthe same in tandem; said' first and second diaphragms defining a secondfuel chamber'therebetween," said first fuel chamber forminga portion ofsaid" fuel conduit'means intermediate said meteringiorificeand said loadresp'onsivemetering mecha'e nism, said second fuel chamber communicatingwith saidfuel conduit means on the downstream side'of said loadresponsive metering mechanism, the fuel pressure dinerential': acrosssaid load responsive metering mechanism being effective to'bias saidcoupled diaphragms inbne axial direction, engine speed-responsivegovernor means" foriactu'ating said coupled diaphragms in the otheraxial direction, said governor means including an axially movableelement for engaging and actuatingsaid coupled diaphragms; anenginepowered adaptor rotatably mount ed within said housing; andcentrifugal weights carried by said adaptor, said centrifugalweight's'having portions" engageable with said axially movable element.

8. The combinationas set forth in claim 7 wherein said-seconddiaphragmis substantially smaller than said first diaphragm, and wherein thecharacteristicsof said governor mechanism are such that the axial forceexerted upo'n saidaxially movable element is substantially constant at agiven engine speed regardless of the axial position of said axiallymovabl'e element.-

9; The' combination as set forth in claim 8 wherein said first" and saidsecond diaphragm, said axially mov' able elementgand said centrifugalweights are'axiallyar'-' ranged. 7

l0. In a fu'elinjection system for a liquid fuel engine havinga fuelpressure source and a fuel delivery con duit extending from said sourceto said engine, an engine speed sensing metering mechanism including ahousing;

a fuel metering orifice in said housing forming a -por-' t-ion of saidfuel delivery conduit, a movable fuel metering'element registering withsaid orifice for progressively restricting: the latter upon movement ofsaid metering element, a first fiexiblediaphragm in' said" housingpartlydefining a first fuel chamber on one side thereof, saidfirstlfu'el chamber communicating with said orifice, a sec ond' flexiblediaphragm in said housing, means for cou- 1 p1ing'isaid"first--andsecond diaphragms together for op citation" of the same in tandem, meansfor biasing said metering element in 'one direction toward a flowrestricting' position with respect to said orifice, a portion of saidmetering element contacting said coupled diaphragms,

said diaphragms being adapted to urge said metering element intheopposite axial direction, said first and second diaphragms-definingasecond fuel chamber therebetween;

p'assage'means interconnecting said second fuel chamber with saiddelivery conduit at a location downstream from saidrfuel -meteringsorifice, the fuel pressure differential between said fuel chamber andsaid downstream location being effective to urge said coupled diaphragmsin said one axial direction, and engine speed responsive governor meansfor actuating said coupleddiaphragms in said opposite axial direction,said governor means including an axially movable element for engagingand actuating said diaphragm coupling means, an engine powered adaptorrotatably mounted within said housing and centrifugal weights carried bysaid adaptor, said centrifugal weights having portions engageable withsaid axially movable element.

11. In a fuel injection system for a multiple cylinder internalcombustion engine, said system including a low pressure, air atomizing,liquid fuel nozzle means for supplying the engine cylinders with acombustible charge of atomized fuel, a low pressure fuel and air pumpingmechanism, separate fuel and air conduits interconnecting said pumpingmechanism and said nozzles, and a first fuel flow restricting meanslocated in said fuel conduit; an engine speed sensitive meteringmechanism comprising an orifice disposed in and forming a portion ofsaid fuel conduit, a metering element registering with said orifice, aflexible diaphragm partly defining a fuel chamber communicating withsaid orifice, a second diaphragm mounted adjacent said first diaphragmand defining a second fuel chamber, auxiliary conduit meansinterconnecting said second fuel chamber and said fuel conduit on thedownstream side of said flow restricting means, said metering elementbeing adapted to be actuated by said first diaphragm, and an enginespeed responsive governor means for biasing said first diaphragm in anaxial direction to cause a decrease in the degree of restriction of saidorifice upon an increase in engine speed, the pressure differentialacross said fiow restricting means being effective to bias said firstdiaphragm in the other axial direction.

12. The combination as set forth in claim 11 wherein said diaphragms arecoupled for simultaneous movement and wherein said governor meansincludes an axially movable portion engaged with said coupled diaphragm,an engine driven adaptor mounted for rotation about a central axis, andcentrifugal weights carried by said adaptor, said weights beingengageable with said axially movable portion and adapted to adjust thesame upon a variation in engine speed, said metering element, saiddiaphragm, said axially movable governor portion, and said centrifugalweights being coaxially arranged.

13. In a fuel control system for a liquid fuel engine having a fuelsource and fuel delivery conduit means extending from said source tosaid engine, an engine speed responsive fuel metering unit having ahollow portion, shiftable means partitioning said hollow portion intofirst and second fuel chambers and being adapted to be shifted by theforce of a fuel pressure differential between said chambers, said firstchamber comprising a portion of said conduit means and the latterincluding a fuel metering aperture upstream from said first chamber andcommunicating therewith to deliver fuel thereinto, a movable fuelmetering element cooperable with said aperture for progressivelyrestricting the same and being adapted to be actuated by said shiftablemeans, said second chamber communicating with said fuel delivery meansat a location downstream from said first chamber, and engine speedresponsive governor means having a shiftable portion, shiftable sealingmeans partially defining said second chamber, a shaft extending throughsaid sealing means and operatively connecting the shiftable portion ofsaid governor means and said shiftable means to shift the latter to varythe degree (pf restriction of said aperture as a function of the enginespeed.

14. The combination according to claim 13 wherein the fuel pressuredifferential between said first fuel chamber and said locationdownstream is effective to urge said shiftable means and meteringelement in the direction tending to restrict said aperture, and saidgovernor means is effective to urge said shiftable means and meteringelement in the opposite direction with a force which is a directfunction of the engine speed.

15. The combination according to claim 14 and comprising in addition anengine load responsive fuel metering mechanism disposed in said conduitmeans downstream of said first fuel chamber, and said locationdownstream being downstream of said load responsive fuel meteringmechanism. 7

16. In a fuel control system for a liquid fuel engine having a fuelsource and fuel delivery conduit means extending from said source tosaid engine, an engine speed responsive fuel metering unit having ahollow portion, shiftable means partitioning said hollow portion intofirst and second fuel chambers and being adapted to be shifted by theforce of a fuel pressure differential between said chambers, said firstchamber comprising a portion of said conduit means and the latterincluding a fuel metering aperture communicating with said firstchamber, a movable fuel metering element cooperable with said aperturefor progressively restricting the same and being adapted to be actuatedby said shiftable means, engine speed re sponsive governor means havinga shiftable portion cooperable with said shiftable means and beingeffective to shift the latter to vary the degree of restriction of saidaperture as a function of the engine speed, an engine load responsivemetering mechanism disposed in said conduit means downstream of saidfirst chamber and metering aperture, and fluid passage means connectingsaid second chamber with said conduit means at a location downstreamfrom said load responsive metering mechanism effective to equalize thefuel pressure between said location and second chamber.

17. The combination according to claim 16 wherein said load responsivemetering mechanism comprises a second fuel metering aperture defining apart of said conduit means, a shiftable pressure responsive memberhaving one side exposed to the engine manifold pressure to be shiftedthereby, a second movable fuel metering element operatively coupled withsaid member to be shifted thereby and being cooperable with said secondaperture for progressively restricting the same, and resilient biasingmeans yieldingly urging said member and second metering element to apredetermined position, said biasing means having one spring ratethroughout one range of movement of said member and having anotherspring rate throughout another range of movement of said member.

18. The combination according to claim 16 wherein said load responsivemetering mechanism comprises a second fuel metering aperture defining apart of said conduit means, a shiftable pressure responsive memberhaving one side exposed to the engine intake manifold pressure to beshifted thereby, a second shiftable fuel metering element operativelycoupled with said member to be shifted in one direction or the oppositeresponsive toa decrease or an increase respectively in said manifoldpressure, said second metering element and aperture being cooperable torestrict the latter progressively upon shifting of the former in saidone direction, resilient means biasing said member to shift said secondmetering element in said opposite direction, said resilient means havingone spring rate throughout one range of movement of said memberresponsive to a comparatively high manifold pressure and having arelatively higher spring rate throughout another range of movement ofsaid member responsive to a lower manifold pressure.

19. In a fuel control system for a liquid fuel engine having a fuelsource and fuel delivery conduit means extending from said source tosaid engine, an engine speed responsive fuel metering unit having ahollow portion, shiftable means partitioning said hollow portion intofirst and second fuel chambers and being adapted to be shifted by theforce of a fuel'pressure differential between said chambers, saidifirstchamber comprising a portion of said conduit means and the latterincluding a fuel metering aperture upstream from said first chamber andcommunicating therewith to deliver fuel thereinto, a movable fuelmetering element cooperable with said aperture for progressivelyrestricting the same and being adapted to be actuated by said shiftablemeans, engine speed responsive governor meanshaving a shiftable portioncooperable 'with said shiftable means and being effec tive to shift thelatter to 'vary the degree of restriction of said aperture as a functionof the engine speed, a load responsive metering mechanism comprising asecond fuel metering aperture defining a part of said conduit means, ashiftable pressure responsive member having one side exposed to theintake manifold pressure to be shifted thereby, a second shiftable fuelmetering element opera'ti-vely coupled with said member to be shifted inone direction or the opposite responsive to a decrease or an increaserespectively in said manifold pressure, said second metering element andaperture being coopera-ble to restrict the latter progressively uponshifting of the former in said one direction, resilient means biasingsaid member to shift said second metering element in said oppositedirection, said resilient means having one spring rate throughout onerange of movement of said member responsive to a comparatively highmanifold pressure and having a relatively higher spring rate throughoutanother range of movement of said member responsive to a lower manifoldpressure.

20. In a low pressure liquid fuel injection system for an internalcombustion engine having an intake manifold and a plurality of enginecylinders, separate manifold portions extending to each engine cylinder,at liquid fuel nozzle mounted in each manifold portion, fuel deliveryconduit means communicating with said nozzles, a load sensor unit havinga fuel metering orifice defining a part of said conduit means, said loadsensor unit further including a movable wall, a metering valve elementregistering with said orifice for progressively restricting the same,said metering valve element being operatively associated and movablewith said movable wall, a vacuum passage extending from said load sensorto said intake manifold to subject one side of said movable wall tomanifold vacuum pressure, said vacuum pressure causing movement of saidmovable wall and said metering valve element toward an orifice closingposition, and spring means for biasing said movable wall and saidmetering valve element toward an orifice opening position, said springmeans being characterized by a given spring rate during movement of saidmovable wall within a first range of positions and by another springrate during movement of said movable wall in another range of positionswhereby the variation in fuel delivery rate for a given speed and thevariation in engine horsepower delivered for any given change inmanifold pressure are substantially similar.

21. In a low pressure liquid fuel injection system for an internalcombustion engine having an intake manifold and a plurality of enginecylinders, separate manifold portions extending to each engine cylinder,a liquid fuel nozzle mounted in each manifold portion, fuel deliveryconduit means communicating with said nozzles, a load sensor unit havinga fuel metering orifice defining a part of said conduit means, said loadsensor unit further including a movable wall, a metering valve elementregistering with said orifice for progressively restricting the same,said metering valve element being operatively associated and movablewith said movable wall, a vacuum passage extending from said load sensorto said intake manifold to subject one side of said movable wall tomanifold vacuum pressure, said vacuum pressure causing move ment of saidmovable wall and said metering valve element toward an orifice closingposition, and spring means for biasing said movable wall and saidmetering valve element toward an orifice opening position, said springmeans including a first spring for biasing said movable wall duringmovement of the same within a given range of operating positions and asecond spring for supplementing the biasing effort of the first springduring movement of said movable wall within another range of operatingpositions.

22. In a low pressure liquid fuel injection system for an internalcombustion engine having an intake manifold and a plurality of enginecylinders, separate manifold portions extending to each engine cylinder,a liquid fuel nozzle mounted in one of said manifold portions, fueldelivery conduit means extending to said nozzle, an engine load sensorunit interposed in said conduit means, said load sensor including ametering orifice defining a part of said conduit means, a metering valveregistering with said orifice for progressively restricting the same, amovable wall, said metering element being operatively associated andmovable with said movable wall, means for applying an engine load signalin the form of intake manifold pressure to one side of said movable wallthereby causing movement of the same toward an orifice opening position,and a variable rate spring means for urging said movable wall toward anorifice closing position whereby the rate of change of fuel delivery tosaid nozzles for any given change in manifold pressure substantiallycorresponds to the change in engine horsepower delivered whichaccompanics such a change in manifold pressure.

23. In a low pressure liquid fuel injection system for an internalcombustion engine, fuel delivery conduit means extending to said engine,an engine load sensor interposed in said conduit means, said load sensorinclud ing fuel metering means defining a part of said conduit means andhaving a movable metering element, variable rate spring means foryieldingly urging said movable element toward a biased position, andmeans for applying an engine load signal to said movable element toactuate the same in response to engine load, thereby to vary the rate offuel delivery to said engine in accordance with said engine load.

24. The combination as claimed in claim 23 wherein said spring means ischaracterized by a given spring rate during movement of said movableelement within a first range of positions and by another spring rateduring movement of said movable element in another range of positions.

25. The combination as claimed in claim 23 wherein said spring means hasa comparatively high spring rate throughout one range of movement ofsaid movable element corresponding to comparatively small engine loadsand has a lesser spring rate throughout another range of movement ofsaid movable element corresponding to comparatively larger engine loads.

References Cited in the file of this patent UNITED STATES PATENTS

